Both types of integrals have received a lot of attention in the literature; all required master integrals are known analytically [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}. Due to the asymptotic expansion, we need to deal with tensor integrals, i.e. integrals for which we can not re-write all numerator structures
in terms of inverse propagators of the integral family. As a consequence, we have to perform a tensor reduction of the numerator structures. Since in the fully hard region of the asymptotic expansion only tadpole
integrals can appear, and in all other regions both types of integrals appear, it is advantageous to perform the tensor reduction for the tadpole integrals. For one- and two-loop integral families, there are general
algorithms for treating tensor tadpole integrals of an arbitrary rank [10]}. These are implemented in MATAD [11]}.
At three and four loops, we have implemented routines to reduce tensors up to rank 10. This is a sufficient
rank to expand the form factor up to \(M_t^{-6}\) .
After tensor reduction we perform an integration-by-parts reduction of the three and four loop tadpole integrals,
as well as the massless form factor integrals, in order to obtain the \(h\rightarrow \gamma \gamma \)  form factor in
terms of master integrals. For this we use LiteRed [12]}, [13]} and FIRE6[14]}.
